Rotary buffing pad

ABSTRACT

Provided is a flat-faced buffing pad that includes a plurality of apertures of variable size. The apertures are generally larger in the areas toward the center of the pad, while being generally smaller in the areas toward the periphery of the pad. Some embodiments further include apertures disposed along one or more concentric circular rings located along the front surface and generally symmetrical about the rotation axis. These configurations of apertures provide both superior cut performance and superior finish. Moreover, these configurations minimize several undesirable aspects in a polishing operation, such as slinging of the polishing compound, vibration, wobbling, and drag felt by the operator as the rotary pad slides across the surface to be polished.

FIELD OF THE INVENTION

Buffing pads are provided for polishing the surface of a workpiece. Moreparticularly, patterned rotary buffing pads are provided for polishingthe surface of a workpiece.

BACKGROUND

The visual appearance of painted surfaces, for example, exterior paintedautomotive and marine surfaces is an important aesthetic property.Original equipment manufacturer and aftermarket industries have devotedmany resources to the development and application of paint systems thatprovide aesthetic properties such as, for example, low haze and gooddistinctness of image. It is commonplace for vehicle and boatmanufacturers to use a base coat and clear coat paint system. The basecoat provides the desired color, while the clear coat, which is appliedover the base coat, provides a transparent scratch and chip-resistantprotective coat. Such paint systems, however, have the tendency tomagnify defects (for example, scratches, haze, and dust nibs) in eitherthe base coat or the clear coat. One common method for imparting, orrestoring, a high quality appearance to the paint system uses amulti-step process.

First, the defects are abraded using a coated abrasive product with afine abrasive particle size, for example, sandpaper, or a structuredabrasive article. This step provides rapid removal of the defects, buttypically leaves scuff, or “swirl” marks, and sometimes scratches, thatneed to be removed. Next, the swirl marks are removed by buffing using abuffing composition. The buffing composition is typically an aqueous orpetroleum based medium containing abrasive particles of smaller sizethan the abrasive particles used in the coated abrasive article.However, depending of the paint system, the buffing step may result in asurface with a hazy appearance. The hazy appearance is removed by afinishing step in which the hazy portion of the paint system is buffedwith a finishing composition. The finishing composition is typically anaqueous or petroleum based medium containing abrasive particles ofsmaller size than the abrasive particles used in the buffingcomposition. Finally, residue from the buffing and/or finishingcompositions is removed, for example, with a soft cloth, therebyproducing an aesthetically appealing finish substantially free ofsurface residue.

Buffing pads used in the above polishing steps are generallycompressible to allow even pressure to be applied across the buffingsurfaces. Such pads are often made from either wool or a polymeric foam.While the polishing steps may be a manual process, it can be facilitatedby attaching the buffing pad to an electric or air-driven pneumaticpower tool. As used herein, “polishing steps” include any of the stepsused in restoring or improving a surface, including compounding,buffing, and finishing steps.

The performance of a buffing pad may be appraised on a number offactors. First, the buffing pad provides a certain level of cutperformance (or “cut”), defined as the rate at which the moving padremoves surface defects. Cut performance should be adequately high toallow polishing to be completed within a reasonable amount of time.Second, the buffing pad provides a certain level of finish. The finishprovided by a buffing operation is defined by the smoothness of theresulting surface and can be quantified by measuring “haze”. Hazedecreases with increasing smoothness, and thus should be as low aspossible. Third, the rotary buffing pad can be appraised on userexperience. Here, it is desirable for a rotary buffing pad to engage thesurface to be polished in a controlled manner to reduce the incidence ofjerking or other unpredictable motions (known as “chatter”) of the powertool during the polishing process. This assists the operator inmaintaining a high degree of control over the orientation of the pad andhelps avoid inadvertent gouging of the workpiece.

SUMMARY

In buffing applications, it is often a challenge to achieve both goodcut and fine finish simultaneously. Modifications to the buffing pad orabrasive compound that enhance cutting performance often lead to acoarser finish. Conversely, modifications which lead to a finer finishoften also tend to reduce the rate of abrasion and thereby degrade cutperformance. The apparent inverse relationship between cut performanceand finish has been a source of frustration to many of skill in the art.

Herein are provided rotary buffing pads which overcome the dilemma facedby one desiring to achieve both superior cut performance and a finefinish. This combination of advantages is provided by using a flat-facedbuffing pad that includes a plurality of apertures of variable size. Theapertures are generally larger in the areas toward the center of thepad, while being generally smaller in the areas toward the periphery ofthe pad. This synergistic arrangement of large and small aperturesprovides both superior cut performance and a superior finish.

This configuration further provides other unexpected advantages overconventional foam buffing pads. First, the center aperturesadvantageously capture excess abrasive composition thereby reducing theamount of liquid sling during the buffing process and therefore reducingboth waste and clean up time after the operation is completed. Second,the amount of vibration, or “chatter”, felt by the operator during thebuffing process is maintained at low levels. Reduced vibration in turnleads to reduced fatigue and enhanced operator comfort. Third, locatingthe larger apertures toward the center of the pad improves operatorcontrol by reducing the drag resistance due to the center of the pad andalso preventing the pad from wobbling during the buffing process. Sincewobbling can cause the buffing pad to jump or jerk across the surface,this configuration improves operator control and reduces the risk ofdamaging the surface being polished.

In one aspect, a rotary buffing pad is provided, comprising a substratehaving a front surface, back surface, and a rotation axis perpendicularto the front and back surfaces, the substrate further comprising aninner region adjacent to and surrounding the rotation axis, an outerregion surrounding the inner region, a plurality of first apertureshaving a first average size located within the inner region andextending from the front surface toward the back surface; and aplurality of second apertures having a second average size locatedwithin the outer region and extending from the front surface toward theback surface, wherein the first average size is larger than the secondaverage size.

In another aspect, a rotary buffing pad is provided comprising asubstrate having a front surface, back surface, and a rotation axisperpendicular to the front and back surfaces, the substrate furthercomprising an inner region adjacent to and surrounding the rotationaxis, an outer region surrounding the inner region, a plurality of firstapertures having a first aperture density located within the innerregion and extending from the front surface toward the back surface, anda plurality of second apertures having a second aperture density locatedwithin the outer region and extending from the front surface toward theback surface, wherein the first aperture density is larger than thesecond aperture density.

In still another aspect, a rotary buffing pad is provided comprising asubstrate having a front surface, back surface, and a rotation axisperpendicular to the front and back surfaces, the substrate furthercomprising an inner region adjacent to and surrounding the rotationaxis, an outer region surrounding the inner region, a plurality of firstapertures having a first average size located within the inner regionand extending from the front surface toward the back surface, aplurality of second apertures having a second average size locatedwithin the outer region and extending from the front surface toward theback surface, wherein the first average size is larger than the secondaverage size, and wherein the outer region further comprises at leastone annular region and wherein the plurality of second apertures furthercomprises a second subset of second apertures located in the at leastone annular region, the second subset extending from the front surfacetoward the back surface and being disposed along at least one circularring, each circular ring being coplanar with the front surface andgenerally symmetrical about the rotation axis.

In yet another aspect, a rotary buffing pad is provided comprising asubstrate having a front surface, back surface, and a rotation axisperpendicular to the front and back surfaces, the substrate furthercomprising an inner region adjacent to and surrounding the rotationaxis, an outer region surrounding the inner region, and a plurality ofapertures extending from the front surface toward the back surface,wherein the apertures have a distribution of sizes and the apertureshaving relatively large size are predominantly located in the innerregion relative to the outer region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a buffing pad according to one exemplaryembodiment of the invention;

FIG. 2 is an elevational cross-sectional view of the buffing pad alongthe line 2-2 in FIG. 1;

FIG. 3 is a perspective view of the buffing pad in FIGS. 1-2, looking atthe back surface;

FIG. 4 is a magnified fragmentary front view of the buffing pad shown inthe rectangular inset 4 of FIG. 1; and

FIG. 5 is a front view of a buffing pad according to an alternativeembodiment of the invention.

DEFINTIONS

As used herein:

-   “Aperture” refers to an opening in an article which may or may not    penetrate through the article;-   “Aperture spacing” refers to the center-to-center distance between    two neighboring apertures;-   “Compressible” refers to a material that reduces in volume upon    application of pressure;-   “Diameter” refers to the largest lateral dimension; and-   “Aperture density” refers to the total population of apertures    located within a given region divided by the total surface area of    that region.

DETAILED DESCRIPTION

The following description is directed to buffing pads useful forremoving defects from a surface and polishing the surface to a finefinish. These buffing pads are especially useful in the automotive andmarine applications, where there is a need to polish a painted exteriorsurface to produce a glossy, aesthetic appearance. However, the buffingpads are not limited to these applications. For example, they may beuseful on any other painted surfaces or even non-painted surfaces, andare not limited to polishing operations on any particular type ofarticle. For example, workpiece surfaces may include marbled, varnished,composite, or gel coated surfaces.

Moreover, buffing pads are not limited to a specific method of use. Anyof a wide variety of abrasive polishes and compounds, both in liquid andsolid form, may be advantageously used with these buffing pads toachieve a desirable surface finish. Various power tools may be used togenerate the relative motion between the buffing pad and the surface tobe polished. Moreover, the application of these pads is not restrictedto any particular stage of a workflow used to polish an article. Forexample, they may be used as a first step, intermediate step, or laststep of a multi-step polishing method. Alternatively, these buffing padsmay be used in a single-step polishing method.

An exemplary buffing pad according to one embodiment is illustrated inFIGS. 1-4 and designated by the numeral 100. As shown in front view byFIG. 1, the buffing pad 100 has a substrate 102 with a front surface104. The front surface 104 is generally flat and has a circular shape inplan view. While not shown here, the front surface 104 may also assumenon-circular shapes. As shown, the substrate 102 further includes a sidesurface 106 and a back surface 108. Optionally and as shown, a backinglayer 110, denoted by the dashed lines, extends across nearly all of theback surface 108. In one exemplary embodiment, the buffing pad 100 hasan overall diameter of about 8.0 inches (20.3 centimeters (cm)) and athickness of about 1.5 inches (3.8 cm). In this description, the “front”is defined as the side that contacts the workpiece and the “back” is theopposite surface.

When used in a buffing operation, the buffing pad 100 rotates about arotation axis 112, shown in FIGS. 1 and 2. The rotation axis 112 isperpendicular to the front surface 104 and passes through the center ofthe buffing pad 100. In the embodiment shown, the substrate 102 issymmetrically disposed about the rotation axis 112 to help minimizewobbling of the buffing pad 100 during operation.

In some embodiments, the substrate 102 is made from a compressiblematerial, such as a polymeric foam. Exemplary substrates having thisproperty include open-celled polyurethane foams. Open-celled foams areadvantageous in that they can be made soft and compliant and do notsignificantly expand in the side directions when compressed from the topand bottom directions. Open-celled foams may also allow limitedpermeability to the buffing polish or compound material. Suchpermeability may advantageously improve overall retention of the polishor compound material on the pad 100 during a polishing operation. Othercommercial foams are also possible, such as those disclosed in issuedU.S. Pat. No. 4,962,562 (Englund, et al.). In exemplary embodiments, thestiffness of the substrate 102, as measured by the pressure required toproduce a compression to 25% of original volume (or 25% Compression LoadDeflection), ranges from 0.3 to 1 pound per square inch (2.1 to 6.9kiloPascals (kPa)).

The optional backing layer 110 preferably has a flexural modulus greaterthan that of the substrate 102 and augments the stiffness along the backside of the buffing pad 100. As increasing the stiffness of the backinglayer 110 generally increases the rate of cut, the flexural modulus canbe tailored to provide the rate of cut desired for the application. Thebacking layer 110 can be coupled to the back surface 108 of thesubstrate 102 by physical means such as thermal lamination.Alternatively, the backing layer 110 may be adhesively bonded to thesubstrate 102.

Optionally, the backing layer 110 may include a fibrous material, suchas a scrim or non-woven material. Advantageously, the fibrous materialcan facilitate coupling the buffing pad 100 to a power tool. In someembodiments, for example, the backing layer 100 includes one-half of ahook and loop attachment system, the other half being disposed on aplate affixed to the power tool. Such an attachment system secures thebuffing pad 100 to the power tool while allowing convenient attachmentand removal of pads between operations.

As particularly shown in FIG. 1, the substrate 102 includes two mutuallyexclusive regions, an inner region 114 and an outer region 116. Theinner region 114, defined as the portion of the substrate 102 locatedwithin the hexagonal dashed loop A′, is both adjacent to and surroundingthe rotation axis 112. In some embodiments, the inner region 114 issymmetrically disposed about the axis 112. While the inner region 114depicted in FIG. 1 happens to have a hexagonal shape, other shapes (forexample, a square, circle, or octagon) are also possible. Preferably,the inner region 114 has a diameter ranging from 20 to 40 percent of theoverall diameter of the substrate 102. The outer region 116 is definedas the portion of the substrate 102 located outside of the dashed loopA′. The outer region 116 surrounds the inner region 114 and is bothcontiguous and concentric with the inner region 114.

It is noted here that both the inner and outer regions 114,116 are solidthree dimensional shapes. Therefore, these regions 114,116 are definednot only by the visible areas of the front surface 104 shown in FIG. 1but also those portions of the substrate 102 located directly thereunder(i.e. beneath the plane of the page in perpendicular view). That is, theregions 114 and 116 include the front surface 104 of the substrate 102and also have the depth or thickness of the substrate 102.

A plurality of first apertures 120 and a plurality of second apertures122 extend from the front surface 104 toward the back surface 108 atdifferent locations along the inner and outer regions 114,116 ofsubstrate 102.

The plurality of first apertures 120 include all of the aperturespresent within the inner region 114. Optionally and as shown, the firstapertures 120 have a generally uniform size and shape and aredistributed evenly across the inner region 114 in a close packed (e.g.square, hexagonal) arrangement such that there is a constant spacingbetween neighboring apertures 120. As an alternative, the apertures 120may be uniformly spread across the front surface 104 but randomized withirregular spacing between neighboring apertures 120. As anotheralternative, the apertures 120 may have an overall distribution that isnon-uniform across the inner region 114.

Optionally and as shown in this embodiment, the plurality of secondapertures 122 includes first and second subsets 123,124 of apertures.The first and second subsets 123,124 of apertures include all of theapertures present within the outer region 116, and are distinguishablefrom each other based on having different arrangements across the frontsurface 104 and different size/shape characteristics. Although bothsubsets 123,124 of apertures are shown, the outer region 116 may includeonly the first subset 123 or only the second subset 124.

As shown in FIG. 1, the first subset 123 of the second apertures 122 arearranged in a series of discrete and replicated polygonal groupings (orclusters) that are spaced apart from each another. In this particularexample, each grouping is hexagonal in shape and consists of sevenapertures each having the same size and shape and being equidistant fromits closest neighboring aperture(s). The hexagonal groupings shown hereare exemplary, however, and other polygonal or even circular groupingscan also be used. As another alternative, the first subset 123 can beevenly distributed across the outer region 116 in a configurationsimilar to that of the first apertures 120. Although not shown here, thefirst subset 123 can include all of the apertures present within theouter region 114.

Optionally and as shown in FIG. 1, the second subset 124 of the secondapertures 122 are disposed along three generally circular rings 140located within the outer region 116. FIG. 4 is a magnified view of therectangular inset shown in FIG. 1 and shows the outermost ring 140 inmore detail. As shown, the second subset 124 of apertures are located inan annular region 118 within in the outer region 116. The annular region118 is defined herein as the portion of the outer region 116 boundedbetween the circular dashed lines B′-B′ and B″-B″, shown in fragmentaryview in FIG. 4. While not shown in their entirety, the lines B′-B′ andB″-B″ are imaginary concentric circles located on the front surface 104and symmetrically disposed about the rotation axis 112. Like the innerand outer regions 114,116, the annular region 118 is a three-dimensionalshape that includes not only the portions of the front surface 104located between the lines B′-B′ and B″-B″, but also portions of thesubstrate 102 located directly thereunder (i.e. beneath the plane of thepage in perpendicular view). Although exactly three rings 140 are shownin FIG. 1, more or fewer than three rings are also possible. Optionallybut not shown here, the second subset 124 can include all of theapertures present within the outer region 114.

In the embodiment shown, the second subset 124 of apertures have agenerally uniform aperture diameter. In other words, the diameters ofthe apertures 124 are not only generally uniform along each individualring 140 but also generally uniform across all three of the rings 140.Further, neighboring apertures 124 display a certain spacing (asmeasured between the centers of the apertures) which is generallyuniform across the rings 140. Preferably, the ratio between the certaindiameter to the certain spacing is at least 0.2. More preferably, theratio between the certain diameter to the certain spacing is at least0.3. Most preferably, the ratio between the certain diameter to thecertain spacing is at least 0.35. As shown in FIG. 1, the three rings140 are coplanar with the front surface 104, concentric with each otherand symmetrically disposed about the rotation axis 112. Optionally, thethree rings 140 are evenly spaced apart from each other in radialdirections, although this need not be the case.

FIG. 2 shows the apertures 120,123,124 in cross-section, thecross-section being taken along cutting plane 3-3 in FIG. 1. As can beseen in FIG. 2, the apertures 120,122 within the substrate 102 have adistribution of sizes, where the plurality of first apertures 120 withinthe inner region 114 have an average size larger than that of theplurality of second apertures 122 within the outer region 116. In otherwords, the apertures 120,122 of relatively large average size arepredominantly located in the inner region 114 relative to the outerregion 116.

The “size” of a given aperture, as used herein, can refer to anydimension of the aperture. For example, the size may represent thediameter, perimeter, inner surface area, or depth of the aperture,volume occupied by the aperture, or combinations thereof. In FIG. 2, forexample, both the average diameter and average depth of the plurality offirst apertures 120 is larger than those of the plurality of secondapertures 122. Likewise in this embodiment, the average volume occupiedby the plurality of first apertures 120 within the inner region 114 islarger than the average volume occupied by the plurality of secondapertures 122 within the outer region 116.

In exemplary embodiments, the plurality of first apertures 120 have anaverage depth ranging from 8 to 12 mm, an average diameter ranging from2 to 4 mm, and average occupied volume ranging from 25 to 150 cubic mm.In other embodiments, the first subset 123 of apertures have an averagedepth ranging from 3.5 to 7.5 mm, an average diameter ranging from 3 to5 mm, and average occupied volume ranging from 25 to 147 cubic mm. Instill other embodiments, the second subset 124 of apertures have anaverage depth ranging from 9 to 13 mm, an average diameter ranging from0.5 to 1.5 mm, and average occupied volume ranging from 1.6 to 25 cubicmm.

In addition to differences in dimensions, the aperture density (inapertures per unit area) of the plurality of first apertures 120 overthe front side of the inner region 114 is greater than that of theplurality of second apertures 122 over the front side of the outerregion 116. In some embodiments, the plurality of first apertures 120have a aperture density ranging from 1.5 to 5.0 per square centimeter,while the plurality of second apertures 122 have a aperture densityranging from 0.8 to 1.5 per square centimeter over their respectiveareas.

The apertures 120,123,124, as shown in FIGS. 1 and 2, are generallycylindrical in cross-sectional shape. Optionally, some of the apertures120,123,124 are non-cylindrical. For example, one or more of theapertures 120,123,124 may have rounded bottoms, tapered walls, or evenreverse tapered walls where the lateral dimension increases withincreasing depth. In some embodiments, the apertures 120,123,124 have anelongated shape in plan view (i.e. as viewed normal to the front surface104). Such elongated apertures may be oriented in either the radialdirection, the tangential direction, or at some intermediate anglebetween the two.

Preferably, the buffing pad 100 uses apertures with a length-to-widthaspect ratio, measured in plan view, that does not exceed 2:1. Use ofdiscrete apertures with a relatively small aspect ratio is advantageousbecause such apertures are resistant to undue expansion during apolishing operation. Expansion of an aperture can allow compounding orpolishing material to accumulate and become trapped in the pad.Agglomerations of abrasive material, if sufficiently large, can scratchthe workpiece and degrade haze performance. It was additionally observedthat expansion of an elongated aperture can even cause the sidewalls ofthe aperture to contact the workpiece, again causing undesirablescratches.

As shown in FIGS. 1, 2, and 4, the plurality of first apertures 120 andthe first and second subsets 123,124 of apertures each has a uniformaperture size within its respective group. However, this need not be thecase. For example, any of the apertures 120,123,124 could display asignificant variability in size, either by choice or as a result ofmanufacturing tolerances. It is further contemplated that thisvariability may even result in overlap between the size ranges of theapertures 120,123, the apertures 123,124, or even the apertures 120,124(as long as the average size of the apertures 120 is larger than theaverage size of the apertures 122).

Similarly, aperture density need not be uniform along the front sides ofregions 114,116. As a result, the plurality of first apertures 120 mayhave an overall aperture density greater than that of the plurality ofsecond apertures 122 even when the former apertures have a localaperture density within a certain area of the inner region 114 less thanthat of the latter apertures within some other area of the outer region116. As such, there may well be significant overlap between numberdensities observed on a local level between the plurality of firstapertures 120 and the plurality of second apertures 122.

While the apertures 120,123,124 extend from the front surface 104 intothe substrate 102 in a generally perpendicular fashion as shown in FIG.2, they may also extend into the substrate 102 at an acute angle to theperpendicular direction if so desired.

The described configuration of the apertures 120,123,124 along thesubstrate 102 of the buffing pad 100 has been shown to provide a numberof unexpected advantages in a polishing operation. First, the apertures120, by virtue of their larger average size relative to the apertures123,124, significantly reduce drag resistance as the center of therotating pad passes over the surface being polished. Second, thegenerally larger apertures 120 also reduce the degree of buckling of thepad 100 that occurs as a result of uneven friction between the frontsurface 104 and the surface being polished. As a result, significantlyless jerking and jumping of the rotary pad occurs during operation. Thealleviation of jerking and jumping in turn improves operator control andreduces strain and fatigue experienced by the operator.

Further advantages are provided by the concentric circular rings 140located along the outer region 116. By partitioning the front surface104 of the pad 100 into four distinct sections, the rings 140 ofapertures 124 help isolate localized deformation of the pad 100 thatoccur during a buffing operation within its particular section. Thisadvantageously prevents propagation of deformation across the entirefront surface 104 and again results in a more manageable and predictablebuffing operation.

Use of apertures of larger sizes in areas near the center of the pad 100also provides superior performance compared with conventional buffingpads. Particularly, these pads 100 provide both increased cut rate andfiner finish responses compared with conventional pads in which theaverage size of the apertures is generally uniform across the frontsurface. This is also an unexpected advantage, because superior cut andfiner finish are often inversely related and it is generally difficultto realize both qualities simultaneously. A buffing pad which providesboth a superior cut and finer finish allows a polishing job to becompleted more efficiently and with less opportunity for operator error.

The apertures 120,123,124 in the substrate 102 may be provided using anynumber of manufacturing methods known to the skilled artisan. In someembodiments, the apertures 120,123,124 are formed by providing asuitable substrate 102, then applying a post-processing method to formthe apertures. Examples of such post-processing methods include thermalembossing methods such as those described in U.S. Patent Publication No.2007/0254567 (McLain) or water jet cutting as described in issued U.S.Pat. No. 5,527,215 (Rubino et al.) and U.S. Patent Publication No.2007/0204420 (Hornby et al.). Alternatively, conventional methods suchas engraving, mechanical boring, or cutting are also possible.

In one preferred method of making the pad 100, a laser is used vaporizethe foam to produce the apertures 120,123,124. Laser cutting leavesbehind a minimum amount of debris, and provides the flexibility for anoperator to make nearly any configuration of apertures desired.Generally, the desired shape can be programmed into a computer aideddrafting (CAD) system that interfaces with software that controls theposition and intensity of the laser. The methods are advantageousbecause they are robust, versatile, and cost effective.

Alternatively, the apertures 120,123,124 may be provided in situ withoutneed for a post-processing step. For example, the apertures 120,123,124can be formed by casting and curing of the foam in a suitably shapedmold.

FIG. 5 shows a buffing pad 200 according to another embodiment of theinvention. Like buffing pad 100, the buffing pad 200 has a substrate 202with a flat, circular front surface 204 extending across the substrate202. The buffing pad 200 further includes apertures 220,223,224 in apattern having characteristics similar to the respective apertures120,123,124 of the buffing pad 100. In an exemplary embodiment, thebuffing pad 200 has a diameter of about 3.25 inches (8.26 cm) and athickness of about 0.88 inches (2.2 cm). Other aspects of the buffingpad 200 are analogous to those already described for pad 100 and shallnot be repeated.

EXAMPLES Comparative A.

A loop backed planar, open cell, polyurethane foam buffing pad,3¼-inches diameter by 1-inch depth (8.26 by 2.54 cm), was obtained underthe trade designation “VP FG 3570-ID, Anthrazit”, from WoodbridgeFoamPartner Company, Chattanooga, Tenn. The foam had an average densityof 31.4 kilograms per cubic meter (kg/m³) and 40% Compression LoadDeflection (CLD) of 8.47 kiloPascals (kPa).

Comparative B.

The face side of the foam buffing pad described in Comparative A, wasformed into a convoluted pattern as described in U.S. Pat. No. 4,962,562(Englund et al.), the disclosure of which is incorporated herein byreference. Convoluted square array dimensions were 1.14 projections persquare inch (0.18 projections per square cm), with a peak-to-valleyheight of 0.16 inches (0.04 cm) and peak-to-peak distance of 0.88 inches(0.35 cm).

Comparative C.

The front side of the foam buffing pad described in Comparative A wasformed into a hexagonal channel array using an Eagle CO₂ Laser, ModelNo. 500, from LMI Technologies, Royal Oak, Mich., according to theconditions listed in Table 1. The pattern was similar to a commerciallyavailable foam buffing pad, type “Hex-Logic”, from Chemical Guys,Hawthorne, Calif.

TABLE 1 Hexagonal Channels Dimensions Width (mm) 3 Depth (mm) 2.5Hexagon Dimension 10 (mm) Laser Settings Power (%) 10 Average Beam0.0014 Diameter (mm) Mark Speed 445 (cm/second) No. of Beam Sweeps 2

Example 1

The buffing pad substrate used in Comparative A was provided and then aseries of apertures were subsequently cut into the exposed face of theplanar foam sheet to provide the aperture pattern shown in FIG. 5. Thepattern cut into the face of the foam includes the first apertures andboth the first and second subsets of the second apertures (hexagonalgroupings and rings). This was accomplished using the Eagle CO₂ Laseroperating according to the conditions listed in Table 2.

TABLE 2 Second apertures First subset (hexagonal Second subset Firstapertures groupings) (rings) Dimensions Diameter (mm) 3 2 1 Depth (mm)10 5.5 11 No. of Apertures 7 6 × 7 11 per radial inch (4.3 per radialcm) Laser Settings Power (%) 15 10 10 Beam Diameter (mm) 1.97 1.97 1.97Mark Speed (cm/second) 508 635 635 No. of Beam Sweeps 3 1 2

Comparative D.

A loop backed planar, open cell, polyurethane foam compounding pad,8-inch diameter by 1-inch depth (20.3 by 2.54 cm), having an averagedensity of 28.7 kilograms per cubic meter (kg/m³) and 25% CLD of 6.52kiloPascals (kPa), obtained from Pinta Foamtec, Inc., Minneapolis, Minn.

Comparative E.

The front side of the foam buffing pad Comparative D was formed into aconvoluted pattern as described in Comparative B, wherein thepeak-to-valley height was increased to 0.44 inches (0.17 cm).

Comparative F.

The front side of the foam buffing pad Comparative D was formed into ahexagonal channel array, as described in Comparative C.

Example 2

The complete aperture pattern as shown in FIGS. 1-2 was formed into thefront side of foam buffing pad of Comparative D according to the methoddescribed in Example 1. As in Example 1, the first apertures and bothfirst and second subsets of the second apertures (hexagonal grouping andrings) were laser cut into the face of the foam.

Comparative G.

A foam buffing pad was made as described in Example 2, except only thesecond subset of the second apertures (rings) were laser cut into theface of the foam.

Comparative H.

A foam buffing pad was made as described in Example 2, except only thefirst subset of second apertures were laser cut into the face of thefoam.

Example 3

A foam buffing pad was made as described in Example 2, except only thefirst apertures and first subset of second apertures (hexagonalgroupings) were laser cut into the face of the foam.

Cut Test 1.

The foam buffing pad of Example 1 and Comparatives A-C, were attached toa 3¼-inch (8.26 cm) diameter foam backup pad available from 3M Company,St. Paul, Minn., under the trade designation “3M Finesse-It Backup Pad,Part No. 84226”. The backup pad was then attached to an air drivenpneumatic buffer, available under the trade designation “Dyna Buffer#57240” from Dynabrade USA, Clarence, N.Y., with a down weight of 5pounds (2.27 kg), and air pressure of 94 pounds per square inch (psi)(648.1 kiloPascals (kPa)) at the face).

A pre-weighed 18 by 24-inch (45.7 by 61.0 cm) painted metal test panel,type “APR 40577” obtained from ACT laboratories, Hillsdale, Mich., wasused as the test substrate. The test panel had the following coatings:E-Coat ED6060; Primer 764204; Basecoat 542AB921 BLACK; ClearcoatRK8148”. The panel was cleaned and dried using a 50% by weight aqueoussolution of isopropanol and a soft lint-free cloth. The panel was thenfixed horizontally in place and 10 grams of buffing compound, type“Finesse-it Purple Polish, Part No. 51056”, obtained from 3M Company,was applied to the center of the panel. The entire panel uniformlybuffed for 2 minutes, using lateral motion and without applyingsubstantial downward hand-force, after which the panel was cleaned anddried as described above. The buffing process was repeated 8 times.

Upon completion the panel was again wiped clean and dried as describedabove, after which the panel was reweighed. Cut was calculated as thedifference between the initial and final weight of the panel. Higher cutvalues are better.

Cut Test 2.

The foam buffing pads of Example 2 and Comparatives D-I, were attachedto an 8-inch (20.3 cm) diameter foam backup pad available from 3MCompany, St. Paul, Minn., under the trade designation “3M Finesse-ItBackup Pad, Part No. 5717”, using an adapter type “5710”, also from 3MCompany. The backup pad was then attached to an electric buffer,available under the trade designation “DeWALT DW849” from DeWALTIndustrial Tool Company, Baltimore, Md., with a down weight of 5 pounds(2.27 kg).

A pre-weighed 45.7 centimeter×61.0 centimeter (18 inch×24 inch) paintedmetal test panel, type “APR 51534(H)” obtained from ACT laboratories,was cleaned and dried according to the method described in Cut Test 1.The test panel had the following coatings: E-Coat ED6060; Primer765224EH; Basecoat 270AB921 BLACK; Clearcoat RK8148”. 10 grams ofrubbing compound, type “Perfect-it Rubbing Compound, Part no. 6085”,obtained from 3M Company, was applied to the test panel and manuallybuffed for 1 minute at 1,400 revolutions per minute (rpm). The panel wascleaned and dried as described above and the buffing process repeatedfour more times, using successively less amounts of rubbing compound of8, 6, 5 and 4 gram, respectively. After the fifth buffing step the testpanel was cleaned, dried and reweighed, and the cut in grams determined.Each Example and Comparative was run in duplicate. As before, higher cutvalues are better.

Haze Measurement.

Haze was measured using a haze gloss meter, Catalog no. “AG-4601” fromByk-Gardener USA, Columbia, Md. Measurements were made before and afterCut Test 1, at the approximate center of each of the four quadrants ofthe test panel (that is, resulting in four measurements), at a 20 degreemeasurement angle. Lower haze values are better.

Comparative Samples A-C and Example 1 were subjected to Cut Test 1 andHaze Measurement. Results are listed in Table 3. Tests on Comparatives Aand B, and Example 1, were run in triplicate.

TABLE 3 Sample Cut (grams)/Std. Dev. Haze/Std. Dev. Test Panel BeforeBuffing Not Applicable 15.3 ± 1.9 Comparative A 0.83 ± 0.34 30.4 ± 1.1Comparative B 1.46 ± 0.01  23.2 ± 2.32 Comparative C 1.33 25.0 ± 2.0Example 1 1.55 ± 0.04 19.05 ± 0.05

Comparatives D-F and Examples 2-3 was subjected to Cut Test 2, induplicate. Results are listed in Table 4.

TABLE 4 Sample Average Cut (grams) Example 2 2.58 Comparative D 2.11Comparative E 2.13 Comparative F 2.26 Comparative G 2.35 Comparative H2.32 Example 3 2.37

All of the patents and patent applications mentioned above are herebyexpressly incorporated by reference. The embodiments described above areillustrative of the present invention and other constructions are alsopossible. Accordingly, the present invention should not be deemedlimited to the embodiments described in detail above and shown in theaccompanying drawings, but instead only by a fair scope of the claimsthat follow along with their equivalents.

1. A rotary buffing pad comprising: a substrate comprising anopen-celled polymeric foam that has a compression deflection value whencompressed to 25 percent of original volume ranging from 2000 to 7000Pascals and having a front surface, back surface, and a rotation axisperpendicular to the front and back surfaces, the substrate furthercomprising: an inner region adjacent to and surrounding the rotationaxis; an outer region surrounding the inner region; a plurality of firstapertures having a first average size located within the inner regionand extending from the front surface toward the back surface; and aplurality of second apertures having a second average size locatedwithin the outer region and extending from the front surface toward theback surface, wherein the first average size is larger than the secondaverage size.
 2. A rotary buffing pad comprising: a substrate comprisingan open-celled polymeric foam that has a compression deflection valuewhen compressed to 25 percent of original volume ranging from 2000 to7000 Pascals and having a front surface, back surface, and a rotationaxis perpendicular to the front and back surfaces, the substrate furthercomprising: an inner region adjacent to and surrounding the rotationaxis; an outer region surrounding the inner region; a plurality of firstapertures having a first aperture density located within the innerregion and extending from the front surface toward the back surface; anda plurality of second apertures having a second aperture density locatedwithin the outer region and extending from the front surface toward theback surface, wherein the first aperture density is larger than thesecond aperture density.
 3. The buffing pad of claim 2, wherein thefirst aperture density ranges from 1.5 to 5.0 per square centimeter andthe second aperture density ranges from 0.8 to 1.5 per squarecentimeter.
 4. The buffing pad of claim 1, wherein the plurality ofsecond apertures include a first subset of second apertures arrangedaccording to a series of replicated polygonal groupings that are spacedapart from each another.
 5. The buffing pad of claim 4, wherein thepolygonal groupings are hexagonal groupings.
 6. The buffing pad of claim1, wherein the plurality of first apertures have a first average depthand the plurality of second apertures have a second average depth thatis less than the first average depth.
 7. The buffing pad of claim 1,wherein the plurality of first apertures have a first average diameterand the plurality of second apertures have a second average diameterthat is less than the first average diameter.
 8. The buffing pad ofclaim 1, wherein the plurality of first apertures occupy a first averagevolume and the plurality of second apertures occupy a second averagevolume that is less than the first average volume.
 9. (canceled)
 10. Thebuffing pad of claim 1, wherein the inner region has a diameter rangingfrom 20 to 40 percent of the diameter of the substrate.
 11. The buffingpad of claim 1, wherein the inner region occupies an area ranging from 4to 16 percent of the total area of the front surface.
 12. (canceled) 13.The buffing pad of claim 1, further comprising a backing layer extendingalong at least a portion of the back surface and having a flexuralmodulus that is greater than that of the substrate.
 14. The buffing padof claim 13, wherein the backing layer comprises a fibrous material tofacilitate coupling to a power tool having a hook face attachmentsurface.
 15. The buffing pad of claim 1, wherein the plurality of firstapertures include all of the apertures present within the inner region.16. The buffing pad of claim 15, wherein the plurality of secondapertures include all of the apertures present within the outer region.17. The buffing pad of claim 1, wherein the outer region furthercomprises at least one annular region and wherein the plurality ofsecond apertures further comprises a second subset of second apertureslocated in the at least one annular region, the second subset extendingfrom the front surface toward the back surface and being disposed alongat least one circular ring, each circular ring being coplanar with thefront surface and generally symmetrical about the rotation axis.
 18. Thebuffing pad of claim 17, wherein the second subset of second apertureshave a certain diameter and a certain spacing between neighboringapertures and the ratio between the certain diameter to the certainspacing is at least 0.2.
 19. The buffing pad of claim 18, wherein theratio between the certain diameter to the certain spacing is at least0.3.
 20. The buffing pad of claim 19, wherein the ratio between thecertain diameter to the certain spacing is at least 0.35.
 21. Thebuffing pad of claim 17, further wherein the at least one annular regioncomprises two or more annular regions and the at least one circular ringcomprises two or more circular rings that are located within therespective annular regions and concentric with each other.
 22. A rotarybuffing pad comprising: a substrate comprising an open-celled polymericfoam that has a compression deflection value when compressed to 25percent of original volume ranging from 2000 to 7000 Pascals and havinga front surface, back surface, and a rotation axis perpendicular to thefront and back surfaces, the substrate further comprising: an innerregion adjacent to and surrounding the rotation axis; an outer regionsurrounding the inner region; and a plurality of apertures extendingfrom the front surface toward the back surface, wherein the apertureshave a distribution of sizes and the apertures having relatively largesize are predominantly located in the inner region relative to the outerregion.